<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="UTF-8" />
		<meta name="viewport" content="width=device-width, initial-scale=1.0" />
		<title>Document</title>
	</head>
	<body>
		<select name="" id="select">
			<option>苹果</option>
			<option>橙子</option>
			<option>葡萄</option>
			<option>香蕉</option>
			<option>柚子</option>
		</select>
		<script src="./common.js"></script>
		<script>
      // 5. 设置下拉框中的默认随机选中项，自己书写结构和js。
      
			var select = my$('#select')
			var options = select.getElementsByTagName('option')
			options[getRandom(0, options.length - 1)].selected = true
		</script>
	</body>
</html>
